1. Field of Invention
The invention relates to a dipole antenna and, in particular, to a triangular dipole antenna which can be applied with the miniaturization product.
2. Related Art
The prosperous development of the wireless transmission industry has carried out various products and techniques for multi-band transmission, so that many new products have the wireless transmission function so as to meet the consumer's demands.
The antenna, which is used for radiating or receiving the electromagnetic wave, is an important component in the wireless transmission system. The wireless transmission system would not work normally such as radiating or receiving data if it lacks of the antenna. Therefore, the antenna is indispensable in the wireless transmission system.
Choosing the suitable antenna not only can be contributive to collocate the appearance of product and to increase transmission characteristics, but also can decrease the production cost. Since the designing method and manufacturing materials are different when designing the antenna for varied application products, and the working frequency band are different in different countries, it is very critical for designing the antenna.
The size of a conventional dipole antenna is unable to reduce effectively in order to achieve the horizontal and vertical polarization effects that the customer requested. Thus, the conventional dipole antenna will occupy a certain area when it is integrated onto the printed circuit board, which results in the increases of the volume and the cost of products. In addition, the conventional dipole antenna works normally between the bandwidths of 2.4 GHz and 2.5 GHz, which is not enough for the present wireless communication requirement.
Additionally, referring to FIG. 1, a regular triangular antenna 1 is to dispose the two regular triangular radiating parts 12, 13 on a surface of a substrate 11 and to feed the signal into the antenna 1 through the feeding point 14 and the grounding 15 to cause the frequency resonance. Accordingly, the antenna can work normally. However, the regular triangular antenna 1 has broader working bandwidth, so that it is hard to regulate the needed band range. Therefore, the regular triangular antenna 1 maybe failed the EMI regulation because it's broader working bandwidth function. In brief, the regular triangular antenna 1 will receive the signal of undesired band range. This will restrict the utilizable of the products.
As mentioned above, the conventional dipole antenna has some problems of the antenna size, which can not be easily reduced, and the insufficient working bandwidth. In addition, the conventional regular triangular antenna has the problem of the broader working band range resulting in improper filtering effect. Therefore, it is an important subject of the invention to provide a dipole antenna, which has smaller size and sufficient working bandwidth, and equips with the proper filtering effect. Accordingly, the size of the applying products can be reduced.